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Transcript
Layers of the Earth Layers of the Earth • If we could take a chunk out of the Earth, we would see that it is made up of different layers. Layers of the Earth • Earth is made up of 3 main layers – Crust – Mantle – Core – Each layer has it’s own individual composition and physical properties. Physical Properties and Composition • Composition= what it’s made of • Physical properties= characteristic that is unique and helps to identify the substance (temp, size, shape, color) • Example: Chocolate Chip Cookies • Composition- flour, eggs, sugar, chocolate chips, baking powder, butter • Properties- round, rough, sweet, tan and black, hot, lumpy, Layers of the Earth(p90) • CRUST – Physical Properties: • outermost layer • thinnest layer (5-70km thick) • Surface temperature • 1% of Earth’s mass • where we live • touches the atmosphere – Composition: • consists of loose rocks & soil 2 Types of Crust • Continental Crust: dry land, granite less dense Oceanic Crust: ocean floor, Basalt, thinner than cont. crust but more dense Layers of the Earth • MANTLE – Physical Properties: • thickest layer (2900km thick) • 1600-4000 F • 66% of earth’s mass • flowing – Composition: • Molten rock –Magma Layers of the Earth • CORE – Physical properties: • HOT! 4000-8000 F • Very dense • High pressure • 4000 miles from surface • 33% of Earth’s mass • About the same size as Mars – Composition: • Iron and Nickel (metals) Crust • Very thin What have you noticed about temperature and pressure? • As you get deeper inside the Earth, temperature Increases • As you get deeper inside the Earth, pressure Increases Layers of the Earth • The 3 main layers of the Earth can be divided further by the way they “act” within the Earth and by their different physical properties. Lithosphere Crust and upper Mantle • outermost layer – includes crust and upper mantle • rigid • divided into pieces or tectonic plates • Rocks and soil Asthenosphere Middle Mantle • composed of solid flowing rock • layer on which pieces of lithosphere move on top (solid rock that flows) – Think of it like caramel Mesosphere Bottom Mantle • strong, lower part of the mantle • layer between asthenosphere and core The Core Outer and Inner • The core is divided into two parts – Outer Core: • Liquid iron and nickel that’s spinning – Inner Core: • Solid iron and nickel • Solid because of all the pressure of the rest of the Earth surrounding it. How do we know? • Seismic waves produced by earthquakes travel at different speeds through solid rock and liquids Homework Directions: • Read through the assigned portions of the power point (for example, you’re first notes homework will be slides #19-37). • You will be reading the slides, and completed the blanks in your guided notes whenever you see the arrow symbol. The portion you need to copy into your notes will be underlined. For example: NOTES Will be underlined The Theory of Continental Drift Continental Drift Discovery Bell Ringer 8.18.14 1. List what you know about tectonic plates: 7th • Made from earth’s crust • When the plates move, they can cause earthquakes, • Plates can create mountains, hills, islands, volcanoes, • Cause supercontinents to form, like pangaea 4th • Plates are all over the world • When plates collide, they can create earthquakes, and volcanoes • Plates are made from crust (dirt, sand, rock) 3rd • Can cause earthquakes and volcanoes • Large plates that cover the entire surface of the earth • As the plates move, Can create landforms like mountains 2nd • • • • • Part of the crust, sit on top of the mantel Oceans are on top of them Continents are on top of the plates THEY’RE MOVING SLOWLY As they move, they cause different things to happen like earthquakes • Volcano eruptions • Their mvmt creates mountains • 2 types: oceanic & continental 1st • Move slowly • Protect from • 3 types of boundaries : transform, divergent, convergent • Plates are part of the crust • On top of the mantle • Connected to earthquakes • Continetal and oceanic crust The World PANGAEA: Supercontinent PANGAEA • Pangaea, also spelled Pangea, was a supercontinent that existed on the Earth millions of years ago and covered about one-third of its surface. • A supercontinent is a very large landmass that is made up of more than one continent. (Notes- define Pangea) PANGAEA • In the case of Pangaea nearly all of the Earth's continents were connected into one large landmass. • It is believed that Pangea began forming about 300 million years ago, was fully together by 270 million years ago and began to separate around 200 million years ago. PANGAEA • If Pangaea still existed, what would it look like with present-day borders? • http://mentalfloss.com/article/58021/mappangea-current-international-borders ALFRED WEGENER: THEORY OF CONTINENTAL DRIFT Wegener found evidence for PANGAEA and proposed the theory of continental drift. Continental Drift (Extra reading: p.95 red book, 182 in Sciencesaurus) • The theory of continental drift states that the continents were once part of a single landmass that broke apart and have moved to their present locations. • can drift apart from one another and have done so in the past For more information about what the continents looked like throughout the Earth’s History go to: htttp://www.ucmp.berkeley.edu/geology/anim1.html Pangaea The continents were once part of a giant landmass called Pangaea which was present on earth 250 million years ago. Can you name the continents in Pangaea? http://kids.earth.nasa.gov/archive/pangaea/Pangaea_game.html WEGENER’S EVIDENCE A. Shapes of the ContinentsIn notebook, write “Wegner’s Evidence” #1 The continents fit together like a puzzle. WEGENER’S EVIDENCE WEGENER’S EVIDENCE B. Mountains #2.Mountain ranges on different continents appear to match; their shapes fit together. • Ex: ranges in Canada match Norway and Sweden • Ex: Appalachian Mtn. match UK mtn Mountain Evidence •The shapes of some mountain ranges on different continents seem to match. •A mountain range in eastern Canada seems to match one found in Norway and Sweden. •Rock Evidence •The age and kind of rocks and minerals along the edge of one continent match rocks and minerals along the edge of another continent. •These matching mountain ranges and rock evidence are across the ocean from each other, yet they look like they fit together like puzzle pieces! Evidence #3- Fossils of the same species were found on separate continents Exit Questions Number 1-3 WEGENER’S EVIDENCE: Glacial Deposits • #4 Scientists have found glaciers were once in areas that are now close to the Equator (& therefore too hot for glaciers!) Evidence of Continental Drift Satellites used to measure the movement of continents • Laser Geodynamics Satellite (LAGEOS) The Plates Move… So what now? Which way? - look at this image – this is the way the plates are moving. • 50 million years- what they predict the world will look like THEORY OF PLATE TECTONICS • THEORY STATES THAT EARTH’S OUTER LAYER (LITHOSPHERE) IS DIVIDED INTO PLATES THAT ARE IN CONSTANT SLOW MOTION MOVING AROUND ON TOP OF THE ASTHENOSPHERE Click to watch video: http://www.youtube.com/watch?v=ryrXAGY1 dmE&noredirect=1 Diagram of Earth’s Tectonic Plates How do the plates move? A.) CONVECTION CURRENTS • This is where HOT Magma(Hot material) from deep within the Earth rises while cooler magma near the surface sinks. Convection currents The asthenosphere consists of solid rock that is flowing. But it’s not all flowing in the same direction. How do we know? B.) Sea-floor spreading This is where new ocean floor is created as two lithospheric plates pull away from one another. These plate movements can cause… 1.) volcanoes 2.) earth quakes 3.) Mountain ranges (to form) 4.) Deep ocean trenches (to form) Seafloor spreading So the plates move. Now What? •As the plates move, they produce changes in Earth’s surface, including volcanoes, earthquakes, mountain ranges, and deepocean trenches. Plate Boundaries • The edges of different pieces of The lithosphere meet at lines called plate boundaries 3 types of plate boundaries: 1.) Convergent 2.) Divergent 3.) Transform 3 Types of Plate Boundaries Divergent Convergent Transform DIVERGENT BOUNDARY = WHEN TWO PLATES ARE MOVING AWAY FROM EACH OTHER MAGMA RISES AND SPILLS OUT FROM UNDER THE PLATES, MAKING NEW CRUST Ex.) rift valley OR trench 3 Types of Boundaries Divergent boundary= two plates move apart • Magma rises and creates new crust or seafloor Ex: sea-floor spreading or a rift Boundary animation Divergent Boundaries © All Rights Reserved. Diverging Africa • http://www.funtrivia.com/triviaquiz/Geography/Famous-Sea-Trenches196059.html Trench game!!! • http://www.learner.org/interactives/dynami cearth/slip4.html Plate boundary game • http://www.extremescience.com/challenge r-deep-video.htm Trench video (.45 sec) • http://www.youtube.com/watch?v=HXrMn R00FHU James Cameron dives to the deepest place on earth in Mariana trench! edge of the Eurasian continent/plate where it drops into a rift valley which lies between the former and the North American tectonic plate. CONVERGENT BOUNDARY = when one plate is pushed under (subducts) another plate. The plate that is pushed under is then recycled back into the asthenosphere. This is when the plates converge 3 Types of Boundaries • Convergent= when two tectonic plates push into one another. Convergent Boundaries • Continental vs. Continental • Continental vs. Oceanic • Oceanic vs. Oceanic Continental vs. Continental •When two continental crustal plates collide, the continents buckle upward and form mountains. Himalayas- Asia Himalayas- Asia Continental vs. Oceanic •The oceanic plate slides under the continental plate. •The continental crust crumbles and forms new mountains or volcanoes. Subduction Zone Oceanic vs. Continental • Ex: Andes mtn in S. America Cascade Mtns. in N. America- Mt. St. Helens • The oceanic plate slides under the continental plate. (Why doesn’t the continental plate slide under the oceanic crust?) • This causes continental crust to crumble and forms new mountains or volcano Oceanic vs. Oceanic •Two oceanic plates collide, one of the oceanic plates slides under the other. •also called a subduction zone Oceanic vs. Oceanic Hawaiian Islands Transform boundary • When two tectonic plates slide past each other horizontally Produces? Earthquakes San Andreas Fault New Madrid Fault WEGENER’S EVIDENCE Continents “fit together” like puzzle pieces Bell Ringer Monday, 8/25/14 Turn to the “Convection lab guide” (page 16-17 in pkt), and answer pre-lab questions #1-3 CONVECTION LAB 1. WHAT QUESTION ARE WE TRYING TO ANSWER TODAY? 1. WHAT QUESTION ARE WE TRYING TO ANSWER TODAY? How do the tectonic plates move? 2. WHAT DO WE ALREADY KNOW ABOUT HOW THE PLATES MOVE? CONVECTION LAB 2. WHAT DO WE ALREADY KNOW ABOUT HOW THE PLATES MOVE? • Plates move very slowly (~2 cm/yr) • HEAT FROM THE EARTH’S CORE PROVIDES THE ENERGY FOR THE PLATES TO MOVE • Have 3 directions they move (transform, convergent, divergent) • THE PLATES ARE ALWAYS MOVING Convection Lab 3. So, HOW is heat from the earth’s core getting to where the tectonic plates are? Through CONDUCTION (touching) and CONVECTION (moving) 4. What is Convection? Convection moves heat by the circulation (or movement) of the heated parts of a liquid or gas. HOT AIR RISES, COLD AIR SINKS How do the plates move? 5.) What are CONVECTION CURRENTS in plate tectonics? This is where hot magma from deep within the Earth rises while cooler magma near the surface sinks Convection Candle Currents • http://www.youtube.com/watch?v=m_lqsyr Opvc • Slide 75: When a candle burns, CONVECTION CURRENTS- rise above the flame. We are not able to see them, however, without special help like the light from a projector. Convection is the transfer of heat by the MOVEMENT of the heated parts of a liquid or gas. • Slide 76: When air is heated, its molecules actually bump into each other, spreading them farther apart and creating MOVEMENT. Think about magma in the mantle: When magma is heated by touching the hot core below it, the magma will RISE. Slide 77: After the magma cools, it will sink back down again to the core, just like the cold water from your ice cube sinks to the bottom of your cup. The core will again heat the magma, and the magma will again rise. The up and down, rising and sinking motions of the magma causes the tectonic plates to move. Complete your diagram: Interactive Video Activity 1. Relationship among earthquakes and plate boundaries? Shallow earthquakes occur along ALL types of plate boundaries. Deep earthquakes more commonly occur along convergent boundaries, especially where oceanic crust collides with oceanic crust. 2. Most divergent boundaries are found in the Atlantic Ocean, or plates that border the Atlantic ocean. (WHY?) Divergent boundaries are usually characterized by mid ocean ridges (WHY?) 3. The three types of convergent boundaries are: Convection in the mantle: • http://www.youtube.com/watch?v=p0dWF _3PYh4 • BGJHS Mission Statement: At BGJHS, all students are empowered to become respectful and responsible 21st century learners and leaders. Bell Ringer 1. When two tectonic plates are moving toward each other, it is called a ________ boundary. a.) transform b.) divergent c.) convergent 2. What was the name of the super continent that used to exist? a.) Eurasia b.) Delora c.) Pangaea Bell Ringer 1. When two tectonic plates are moving toward each other, it is called a ________ boundary. a.) transform b.) divergent c.) convergent 2. What was the name of the super continent that used to exist? a.) Eurasia b.) Delora c.) Pangaea Bell Ringer 1. List the three types of convergent boundary plate collisions: Oceanic crust colliding into oceanic Continental crust colliding into continental Oceanic crust vs. continental 2. What are we learning about today? Bell Ringer 2/26/14 1. What are the three types of plate boundaries? 2. What are the three specific types of convergent boundaries? • The real proof came from our knowledge of evolution; Darwin proved that animals will evolve to adapt to their environment. Therefore, if the dinosaurs found on Africa and South America had not come from the same connected continent, there would have been subtle differences between them, based on their slightly different environments. ORQ Word Bank C. Part “C” Word Bank Geologic features (or events): -Earthquake -Mountains -Volcanic Mountains -Volcanic islands -Ridge Advanced: Bell Ringer 2.11.14 1. Plates move because: a.) Heat in the earth’s core provides energy for movement b.) earthquakes push & move plates c.) Tides push and move plates 2. TRUE or FALSE: Pangaea was the 1st super continent to form on earth Bell Ringer 2.10.14 1. Pangaea was: a.) A time period when the dinosaurs lived b.) A unified ocean c.) A super-continent 2. TRUE or FALSE: Plates below us, and all over the world beneath Earth’s crust are still moving